NEUTROPHIL BEHAVIOR FOLLOWING EXPOSURE TO IN-VIVO OR IN-VITRO ZINC INNORMAL AND ACUTELY-INFLAMED RATS - STUDIES ON LYSOZYME SECRETION, SUPEROXIDE ANION RELEASE AND PLATELET-ADHESION

The mechanism was studied of the anti-inflammatory effect of oral zinc (114 mg/kg/day of elemental metal, given for 14 days) on the developm ent of the carrageenan-induced paw oedema of the rat, and the impact o f in vivo treatment on the activity of neutrophils isolated from the b lood of inflamed and non-inflamed animals. The effects of the in vitro incubation with the metal on either non-inflamed or inflamed neutroph ils coming from zinc-untreated rats were also examined. It was found t hat the administration of oral zinc inhibited markedly the process of ex vivo adhesion of the cells obtained from the inflamed rats (an obse rvation confirmed by the in vitro experiments). In vitro release of ly sozyme and superoxide anion productions were measured: in the absence of zinc, the 30' of pre-incubation carried out before stimulating with PMA did not influence the cell's reactivity of the non-inflamed neutr ophils. It was, on the contrary, capable of significantly reducing tha t of the inflamed ones. As a consequence, it is quite difficult to pro perly interpret the data obtained studying the activity of the cells e xposed to the metal in vitro.